In a mobile communications network, a mobile station (MS) can communicate with a base station (BS) via a relay station (RS). Typically, communication from the MS to the BS takes place over an uplink (UL) channel, and communication from the BS to the MS takes place over a downlink (DL) channel. In most time-division duplex (TDD) relay communication protocols, an MS may transmit a message intended for the BS to an RS in an UL sub-frame. The RS in turn transmits the message to the BS in an RS UL sub-frame. On the other hand, a BS may transmit a message intended for the MS to the RS in a DL sub-frame. The RS then transmits the message to the MS in an RS DL sub-frame.
The above relay scheme is inefficient, because the MS or the BS will have to schedule each of the uplink or downlink transmissions handled by the RS in separate sub-frames. The transmission throughput of a network implementing such a scheme is limited due to inefficient use of bandwidth (i.e., separate channels need to be used for UL and DL of relayed messages). If network coding is applied at the RS, the bandwidth usage of a relay link can be reduced. However, the reduction may be limited if the scheduling processes of UL and DL are operated independently.
More efficient systems and methods are desirable that can overcome the above-noted shortcomings.